305 TBI, tailpipe smoke?
04-29-2011, 04:26 PM
#1
305 TBI, tailpipe smoke?
Well, after several start-ups of my Firebird to test out the cooling system parts I installed (basically just about everything), something else seems to be wrong, and I'm not quite sure what it is.
The car overheated several months back (some steam coming out of the engine when I checked it after pulling over, but nothing too crazy), and I decided to go through and change/upgrade all the essential components of the cooling system (it needed them anyway, radiator, pump, heater core, theromstat, some hoses).
The car seems to take longer to start warming up than it used to, so that seems like a good thing. But what troubles me is that it blows smoke out of the tailpipe while running - and it's mostly white, with traces of grey/blue. The thing is, I can't seem to find any of the classic head gasket symptoms - No sweet smell (there is a gassy/burning smell though), no milky oil, bubbles in the coolant reservoir tank, or nasty stuff on the oil cap.
I suspect that the car may be running rich, but most things I've read seem to indicate that white smoke is typically coolant being burned off. Is it possible I still have a bad head gasket? (I've ran the car for up to 10 min idling, and it doesn't reach operating temp). I've read that cracked heads are another possibility. I need a bit of expert advice on where to begin looking!
The car overheated several months back (some steam coming out of the engine when I checked it after pulling over, but nothing too crazy), and I decided to go through and change/upgrade all the essential components of the cooling system (it needed them anyway, radiator, pump, heater core, theromstat, some hoses).
The car seems to take longer to start warming up than it used to, so that seems like a good thing. But what troubles me is that it blows smoke out of the tailpipe while running - and it's mostly white, with traces of grey/blue. The thing is, I can't seem to find any of the classic head gasket symptoms - No sweet smell (there is a gassy/burning smell though), no milky oil, bubbles in the coolant reservoir tank, or nasty stuff on the oil cap.
I suspect that the car may be running rich, but most things I've read seem to indicate that white smoke is typically coolant being burned off. Is it possible I still have a bad head gasket? (I've ran the car for up to 10 min idling, and it doesn't reach operating temp). I've read that cracked heads are another possibility. I need a bit of expert advice on where to begin looking!
04-29-2011, 07:07 PM
#3
Re: 305 TBI, tailpipe smoke?
Nope. Not losing any coolant, so that's another reason I'm a bit puzzled.
The amount of smoke coming out of the pipes seems a bit excessive to be condensation, so that's why I think something's wrong. Maybe I can shoot a video of it running and post a link to it once I get a chance!
The amount of smoke coming out of the pipes seems a bit excessive to be condensation, so that's why I think something's wrong. Maybe I can shoot a video of it running and post a link to it once I get a chance!
06-06-2011, 12:23 AM
#5
Re: 305 TBI, tailpipe smoke?
Well, I'm long overdue for getting back to everyone on this, but I think I have this one pretty much figured out, and it's not looking too good, lol. I've done a bit more homework on engine stuff, and took a look at the spark plugs earlier today. There's an attached pic that shows what they looked like.
Last time I did anything involving spark plugs, they looked to be a bit brown, but in normal condition. Mine appear to have a thin coating of oil on them, which from what I've read, often indicates bad valve stem seals or piston rings.
Though I thought I needed valve seals before, I'm starting to suspect piston rings, because it takes a few seconds of cranking to start the car cold (compression loss?), and the car has always had occasional misfiring/rough idle that replacing other parts hasn't fixed. Also, now that the weather has warmed up a bit, and I don't have lots of white condensation smoke from the tailpipe when it runs, it's definitely spewing a blue-ish/grey smoke, mostly when giving it gas.
I've heard that valve seals aren't too awful to do, but that piston rings are a fun job, and are a lot of work that often just serves as "buying time" before a rebuild/replacement phase of the motor.
What are my best options? I'm not afraid to get my hands dirty and learn how to fix it if it's worth the trouble (depending what's wrong w/it), but have also thought about hunting down a cheap 350 TBI too, lol. I don't, and won't have the money to pay a machine shop to completely rebuild my 305 for a while (if it does, in fact need a rebuild), nor do I feel it's worth it when I'm planning to go the 350 route eventually anyway.
Any advice appreciated!
Last time I did anything involving spark plugs, they looked to be a bit brown, but in normal condition. Mine appear to have a thin coating of oil on them, which from what I've read, often indicates bad valve stem seals or piston rings.
Though I thought I needed valve seals before, I'm starting to suspect piston rings, because it takes a few seconds of cranking to start the car cold (compression loss?), and the car has always had occasional misfiring/rough idle that replacing other parts hasn't fixed. Also, now that the weather has warmed up a bit, and I don't have lots of white condensation smoke from the tailpipe when it runs, it's definitely spewing a blue-ish/grey smoke, mostly when giving it gas.
I've heard that valve seals aren't too awful to do, but that piston rings are a fun job, and are a lot of work that often just serves as "buying time" before a rebuild/replacement phase of the motor.
What are my best options? I'm not afraid to get my hands dirty and learn how to fix it if it's worth the trouble (depending what's wrong w/it), but have also thought about hunting down a cheap 350 TBI too, lol. I don't, and won't have the money to pay a machine shop to completely rebuild my 305 for a while (if it does, in fact need a rebuild), nor do I feel it's worth it when I'm planning to go the 350 route eventually anyway.
Any advice appreciated!
Last edited by Flightoficarus; 06-06-2011 at 12:27 AM.
06-06-2011, 01:05 PM
#6
Re: 305 TBI, tailpipe smoke?
Check your intake gasket too- I had a brand new one suck through because my new bolts lost torque (centers not even finger tight), and that was the cause of my oil burning problems. Mine were completely coked up in a matter of 1-200 miles. On decel with the converter locked I looked like I was skeeter spraying!
A few seconds to start could also be fuel or voltage related. Check your battery voltage while you start it- if it drops too low, it's on it's way out, you have a bad connection/bad ground, bad cell, etc.
If you are going to the trouble of re-ringing, you might as well take it to a machine shop and have the bores cleaned up. Might cost an extra $150-200 for the shop to bore/hone over the cleaning charge. Wait another month or 2 to squirrel away the money- there's no guarantee that a used motor (even with less miles) won't give you the same issues or worse as soon as you start it up, and then you'll be back to square one. IMHO, your best option is to find a 350 block and utilize it for the rebuild- just be sure if yours is 1 pc RMS, you get a 1 pc RMS block and not a 2pc- otherwise you'll need a new flexplate or flywheel.
Valve seals being not that hard a job is subjective. IMHO, engine out they're easy. Engine in, on a F body, is more a PITA. Especially if it's lowered. If you have easy access to all 8 plug holes, and a good air compressor or 4-6ft of nylon rope, not that big a deal. Key is easy access to all 8 plug holes for shop air or stuffing rope. If they're factory heads, they probably need new guides anyway. Does/did it puff blue briefly when you first start it?
If you have the tools to pull then engine, it doesn't cost that much more to buy a ring compressor, plastigauge, and a good torque wrench, which you might already have.
A few seconds to start could also be fuel or voltage related. Check your battery voltage while you start it- if it drops too low, it's on it's way out, you have a bad connection/bad ground, bad cell, etc.
If you are going to the trouble of re-ringing, you might as well take it to a machine shop and have the bores cleaned up. Might cost an extra $150-200 for the shop to bore/hone over the cleaning charge. Wait another month or 2 to squirrel away the money- there's no guarantee that a used motor (even with less miles) won't give you the same issues or worse as soon as you start it up, and then you'll be back to square one. IMHO, your best option is to find a 350 block and utilize it for the rebuild- just be sure if yours is 1 pc RMS, you get a 1 pc RMS block and not a 2pc- otherwise you'll need a new flexplate or flywheel.
Valve seals being not that hard a job is subjective. IMHO, engine out they're easy. Engine in, on a F body, is more a PITA. Especially if it's lowered. If you have easy access to all 8 plug holes, and a good air compressor or 4-6ft of nylon rope, not that big a deal. Key is easy access to all 8 plug holes for shop air or stuffing rope. If they're factory heads, they probably need new guides anyway. Does/did it puff blue briefly when you first start it?
If you have the tools to pull then engine, it doesn't cost that much more to buy a ring compressor, plastigauge, and a good torque wrench, which you might already have.
06-06-2011, 06:23 PM
#7
Re: 305 TBI, tailpipe smoke?
Hmm. Well the answer is definitely yes as far as the car blowing a puff of blue-ish smoke on start-up. It's done that since I've owned it, and so I suspected in needed valve seals, but now it does that, and blows smoke when revving/accelerating, but not as much when idling. That's what nakes me concerned that the overheat may have done the rings in.
Battery is new, and the car seems to have proper voltage when running, but I can check again to see if it's dropping down when cranking the motor. Oil pressure when cold seemed ok last time I checked. Around 35-40 PSI I think. But it does drop down a bit when the car is warmed up.
Getting access to an engine hoist if need be shouldn't be an issue, but leaving the car elsewhere for longer than a weekend might be if it must be pulled (at least atm). As far as tools go, I'm actually starting school for auto body soon, so many new tools will make their way into my collection before too long
. How much does a good ring compressor go for? I do have a torque wrench, but it's nothing too fancy.
Battery is new, and the car seems to have proper voltage when running, but I can check again to see if it's dropping down when cranking the motor. Oil pressure when cold seemed ok last time I checked. Around 35-40 PSI I think. But it does drop down a bit when the car is warmed up.
Getting access to an engine hoist if need be shouldn't be an issue, but leaving the car elsewhere for longer than a weekend might be if it must be pulled (at least atm). As far as tools go, I'm actually starting school for auto body soon, so many new tools will make their way into my collection before too long
. How much does a good ring compressor go for? I do have a torque wrench, but it's nothing too fancy. Trending Topics
06-06-2011, 07:08 PM
#8
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Re: 305 TBI, tailpipe smoke?
Check the pcv valve, the vacuum pipe that connects to it and the vacuum pipe inlet on the throttle body. On my old car it was fully clogged and blew smoke on start up and when idling/revving it. Cleaned the throttle body and new pcv and no more smoke.
07-02-2011, 02:21 PM
#9
Re: 305 TBI, tailpipe smoke?
Ok, I'm again, long overdue on getting back to this, but with some further inspecting, I'm starting to think there could hopefully be some hope!
That picture I posted was actually of an old plug I had to re-use for the time being (broke a new one on accident, and the old one looked ok before). I checked one of the other (newer) plugs last weekend. It had a dry, black, soot-like coating that was more suggestive of running rich/ignition issues than oil loss. The center electrode also had a bit of white on the tip of it (these plugs were in the car back when it did overheat).
They say the plugs are supposed to be pre-gapped, but how often does that hold true? Aside from checking the plug gap, what else should I check out? Changing valve stem seals is gonna require access to tools I don't have atm, and I'd prefer to check/try the easier solutions to getting this thing to run right first!
Again, the car takes several seconds of cranking to fire up first thing after it's been sitting, but once it's been started, and after I shut it off, it will start up again right away. The amount of time needed to crank for the first start up of the day does not change, even when I've let the car sit for 3-4 weeks or so.
That picture I posted was actually of an old plug I had to re-use for the time being (broke a new one on accident, and the old one looked ok before). I checked one of the other (newer) plugs last weekend. It had a dry, black, soot-like coating that was more suggestive of running rich/ignition issues than oil loss. The center electrode also had a bit of white on the tip of it (these plugs were in the car back when it did overheat).
They say the plugs are supposed to be pre-gapped, but how often does that hold true? Aside from checking the plug gap, what else should I check out? Changing valve stem seals is gonna require access to tools I don't have atm, and I'd prefer to check/try the easier solutions to getting this thing to run right first!
Again, the car takes several seconds of cranking to fire up first thing after it's been sitting, but once it's been started, and after I shut it off, it will start up again right away. The amount of time needed to crank for the first start up of the day does not change, even when I've let the car sit for 3-4 weeks or so.
07-02-2011, 07:21 PM
#10
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Re: 305 TBI, tailpipe smoke?
Did you ever code 22(tps low voltage)sometimes that would cause a little more cranking time or code36(MAF burnoff relay).I think the extra cranking time is causing a little more fuel pumping in, witch is causing the smoke.
Last edited by mantaguy; 07-02-2011 at 07:25 PM.
07-03-2011, 01:01 PM
#11
Re: 305 TBI, tailpipe smoke?
I never got around to checking the engine codes, since I didn't really know how before. I looked it up, and now realize how easy it is! 
But here's the problem. I've done other work on the car that has involved disconnecting the battery, and the ECM before, so from what I've gathered, doesn't this mean the codes have been reset, and I have to try and drive the car until the codes kick in again?
I've been told the MAF could cause rich running before, but I'm also curious, how would I check to see if the fuel injectors are leaking? Maybe it's getting too much fuel that way too?
But here's the problem. I've done other work on the car that has involved disconnecting the battery, and the ECM before, so from what I've gathered, doesn't this mean the codes have been reset, and I have to try and drive the car until the codes kick in again?
I've been told the MAF could cause rich running before, but I'm also curious, how would I check to see if the fuel injectors are leaking? Maybe it's getting too much fuel that way too?
07-04-2011, 06:53 PM
#12
Re: 305 TBI, tailpipe smoke?
BUMP/Update!
I did a diagnostic today, but the only code I pulled up was code 12, which from what I'm told, simply means the computer is operating properly, and in diagnostic mode? I think the codes got reset when I replaced the heater core and battery. Is my only option to try driving the car to get the codes to come back? Or are there other tests I should try first, maybe fuel pressure?
I did a diagnostic today, but the only code I pulled up was code 12, which from what I'm told, simply means the computer is operating properly, and in diagnostic mode? I think the codes got reset when I replaced the heater core and battery. Is my only option to try driving the car to get the codes to come back? Or are there other tests I should try first, maybe fuel pressure?
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